5‐membered lactones 3p, 3q, 16 were obtained in moderate yields. The one‐pot synthesis of kawa lactones 3a, 3r, 3s and formal synthesis of dihydroxycystothiazole A and dihydroxycystothiazole C are presented. To elucidate the stereochemistry of (+)‐annularin G and (−)‐annularin H, the first asymmetric syntheses of these naturalproducts were achieved.